﻿// This software is part of the Autofac IoC container Copyright © 2015 Autofac Contributors http://autofac.org
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
// associated documentation files (the "Software"), to deal in the Software without restriction,
// including without limitation the rights to use, copy, modify, merge, publish, distribute,
// sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
// NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
// OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

using System;
using Microsoft.Extensions.DependencyInjection;

namespace Autofac.Extensions.DependencyInjection
{
  /// <summary>Autofac implementation of the ASP.NET Core <see cref="IServiceProvider"/>.</summary>
  /// <seealso cref="System.IServiceProvider"/>
  /// <seealso cref="Microsoft.Extensions.DependencyInjection.ISupportRequiredService"/>
  public class AutofacServiceProvider : IServiceProvider, ISupportRequiredService, IDisposable
  {
    private readonly IComponentContext _componentContext;

    /// <summary>Initializes a new instance of the <see cref="AutofacServiceProvider"/> class.</summary>
    /// <param name="componentContext">The component context from which services should be resolved.</param>
    public AutofacServiceProvider(IComponentContext componentContext) => _componentContext = componentContext;

    /// <summary>Gets service of type <paramref name="serviceType"/> from the <see cref="AutofacServiceProvider"/> 
    /// and requires it be present.</summary>
    /// <param name="serviceType">An object that specifies the type of service object to get.</param>
    /// <returns>A service object of type <paramref name="serviceType"/>.</returns>
    /// <exception cref="Autofac.Core.Registration.ComponentNotRegisteredException">
    /// Thrown if the <paramref name="serviceType"/> isn't registered with the container.</exception>
    /// <exception cref="Autofac.Core.DependencyResolutionException">
    /// Thrown if the object can't be resolved from the container.</exception>
    public object GetRequiredService(Type serviceType) => _componentContext.Resolve(serviceType);

    /// <summary>Gets the service object of the specified type.</summary>
    /// <param name="serviceType">An object that specifies the type of service object to get.</param>
    /// <returns>A service object of type <paramref name="serviceType"/>; or <see langword="null"/> if there
    /// is no service object of type <paramref name="serviceType"/>.</returns>
    public object GetService(Type serviceType) => _componentContext.ResolveOptional(serviceType);

    public void Dispose() { }
  }
}